The phrase "a relatively long lived" is correct and usable in written English.
It can be used when discussing the lifespan or duration of something in comparison to others.
Example: "The tortoise is known for being a relatively long lived species, often reaching over 100 years of age."
Alternatives: "a comparatively long-lived" or "a notably long-lived".
Many large raptors are relatively long lived, often have a lengthy period of deferred maturity, compete for territories, exploit a wide variety of prey and have a high potential for exploratory behaviour prior to breeding [ 13].
In Figure 8a and b the decays of all samples show the transient species to be relatively long lived, with all traces having a t50% (mΔA at 300 ns) of over 10 μs.
The free signaling Gαo-GDP form is predicted to be relatively long lived (Katanaev and Chornomorets, 2007), and a number of Gαo target proteins have been identified that interact equally well with both of the nucleotide forms of this G protein (Kopein and Katanaev, 2009; Egger-Adam and Katanaev, 2010; Purvanov et al., 2010; Lin and Katanaev, 2013; Lin et al., 2014).
Hence, the relatively long lived charge separation state of SnNb2O6 promised a higher charge separation efficiency and photocatalytic activity.
In the lab, Japanese quail show age-related deterioration in endocrine, behavioral, and sensory system responses; the American kestrel is relatively long lived and shows moderate evidence of senescence in the oldest birds.
Derived from blood monocytes, macrophages are relatively long lived phagocytotic cells of mammalian tissues.
No Mac387 staining was present in pathologic brain and lymphoma tissues suggesting that the CD68 expressing cells present in those tissues were relatively long lived.
As tissue macrophages are relatively long lived, monocytes generated in the bone marrow generally far exceed the numbers required to replenish dying tissue macrophages.
The NMDA receptor is unique in that it is permeable to both sodium and calcium ions, so its electrical current is both agonist- and voltage-dependent, and relatively long lived.
